Semiconductor device and manufacturing method thereof
View Patent ↗A semiconductor device includes an oxide semiconductor layer including a crystalline region over an insulating surface, a source electrode layer and a drain electrode layer in contact with the oxide semiconductor layer, a gate insulating layer covering the oxide semiconductor layer, the source electrode layer, and the drain electrode layer, and a gate electrode layer over the gate insulating layer in a region overlapping with the crystalline region. The crystalline region includes a crystal whose c-axis is aligned in a direction substantially perpendicular to a surface of the oxide semiconductor layer.
1. A semiconductor device comprising:
an oxide semiconductor layer including a crystalline region over a substrate;
a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor layer; and
a gate electrode layer over the oxide semiconductor layer,
wherein the crystalline region includes a crystal whose c-axis is aligned in a direction within ±10° from a perpendicular direction to a surface of the oxide semiconductor layer.
2. The semiconductor device according to claim 1 , wherein a hydrogen concentration of the oxide semiconductor layer is 5×10 19 /cm 3 or less.
3. The semiconductor device according to claim 1 , wherein an energy band gap of the oxide semiconductor layer is 3.0 eV to 3.5 eV.
4. The semiconductor device according to claim 1 , wherein the oxide semiconductor layer contains indium, gallium and zinc.
5. The semiconductor device according to claim 1 , wherein an off-state current of the semiconductor device is 1×10 −13 A or less when a drain voltage is +1 V or +10 V, and a gate voltage is set from −5 V to −20 V.
6. The semiconductor device according to claim 1 , further comprising a gate insulating layer covering the source electrode layer and the drain electrode layer.
7. The semiconductor device according to claim 1 , wherein the semiconductor device is one selected from the group consisting of a personal computer, a personal digital assistant, an electronic book, a cellular phone, a digital camera, and a television set.
8. A semiconductor device comprising:
an oxide semiconductor layer including a crystalline region over a substrate;
a source electrode layer and a drain electrode layer electrically connected to the oxide semiconductor layer; and
a gate electrode layer over the oxide semiconductor layer,
wherein the crystalline region includes a crystal whose c-axis is aligned in a direction within ±10° from a perpendicular direction to a surface of the oxide semiconductor layer, and
wherein a thickness of the crystalline region is 2 nm to 10 nm.
9. The semiconductor device according to claim 8 , wherein a hydrogen concentration of the oxide semiconductor layer is 5×10 19 /cm 3 or less.
10. The semiconductor device according to claim 8 , wherein an energy band gap of the oxide semiconductor layer is 3.0 eV to 3.5 eV.
11. The semiconductor device according to claim 8 , wherein the oxide semiconductor layer contains indium, gallium and zinc.
12. The semiconductor device according to claim 8 , wherein an off-state current of the semiconductor device is 1×10 −13 A or less when a drain voltage is +1 V or +10 V, and a gate voltage is set from −5 V to −20 V.
13. The semiconductor device according to claim 8 , further comprising a gate insulating layer covering the source electrode layer and the drain electrode layer.
14. The semiconductor device according to claim 8 , wherein the semiconductor device is one selected from the group consisting of a personal computer, a personal digital assistant, an electronic book, a cellular phone, a digital camera, and a television set.